Overhead-traveling carrying apparatus

ABSTRACT

This invention has as an object thereof to provide an overhead-traveling carrying apparatus which is capable of inexpensively incorporating countermeasures for detecting the presence of an obstacle such as a human being or a carelessly placed object during the lowering of an object to be carried onto the load port of a semiconductor manufacturing device prior to the contact of the obstacle with the object to be carried, thereby avoiding such contact. A structure is adopted in which obstacle detecting sensors which scan the raising and lowering path between a carriage and the load port of each semiconductor manufacturing apparatus, and which detect the presence of obstacles, are provided on the carriage with attached hoist.

BACKGROUND OF THE INVENTION

[0001] 1. Field of the Invention

[0002] The present invention relates to an overhead-traveling carryingapparatus which travels along a track which is installed overhead, andwhich conveys objects to be carried in a suspended state betweensemiconductor manufacturing apparatuses which are disposed in a cleanroom.

[0003] 2. Background Art

[0004] In production facilities which conduct the manufacturing ofsemiconductor devices, carrying devices are employed which automaticallyconduct the conveyance of semiconductor wafers among a variety ofapparatuses; track-type carrying apparatuses are often employed as suchcarrying apparatuses. In general, in track-type carrying apparatuses,the structure is such that carriages travel along tracks which areinstalled either overhead or on the floor surface, and normally thesemiconductor wafer processes are conducted to the side of the tracks.

[0005] Generally, semiconductor devices are produced via processinginvolving several hundred processes in which a semiconductor wafercomprising silicon or the like is conveyed back and forth between avariety of semiconductor manufacturing apparatuses (wafer processingapparatuses, storage apparatuses, work platforms, buffer apparatuses,and the like) by an overhead-traveling carrying apparatus or the like.

[0006] This will be explained below with reference to FIG. 6. Forexample, in an overhead-traveling carrying apparatus for semiconductormanufacturing apparatuses in a clean room, carriages 3 with attachedhoists, which travel along an overhead track 1 which is not depicted,are employed, and processing is conducted by carrying wafer carriers 6with semiconductor wafers 2 loaded thereon between the semiconductormanufacturing apparatuses 7, or between the semiconductor manufacturingapparatuses 7 and the stocker 7A.

[0007] The carriages 3 with attached hoists depicted in the figurecomprise a traveling part 3 a, which travels along track 1, and a hand5, which is suspended in such a manner as to be fully raised or loweredby a hand suspending part 4 which is provided on this traveling part 3a; the wafer carrier 6, which is placed at the load port 8 of thesemiconductor manufacturing apparatus 7, is grasped by hand 5, and afterthe hand suspending part 4 lifts the hand 5, this is carried along thetrack 1 by traveling part 3 a.

[0008] Within this clean room, as shown in the figure, a plurality ofsemiconductor manufacturing apparatuses 7 are arranged in a parallelfashion along the track 1 which is provided overhead, and the wafercarriers 6 are grasped on load port 8 of each semiconductormanufacturing apparatus 7 by the plurality of carriages 3 with attachedhoists, and are carried to other semiconductor manufacturing apparatuses7.

[0009] The carrying of the semiconductor wafers 2 by theoverhead-traveling carrying apparatus described above is conducted inthe following manner. First, the carriage 3 with an attached hoisttravels along track 1, and stops above a load port 8 which has a wafercarrier 6 which is to be carried. Next, the hand suspending part 4 islowered and the hand 5 descends, and the wafer carrier 6 is held by thehand 5. Then, the hand suspending part 4 is hoisted and the wafercarrier 6 is removed from load port 8, and after this has been hoistedto a maximum height, the carriage 3 with an attached hoist again beginsto travel.

[0010] Next, the carriage is again stopped above the load port 8 of astocker 7A or another semiconductor manufacturing apparatus 7 which isto conduct the subsequent process. The hand suspending part 4 is thenlowered and the hand 5 descends, and after the wafer carrier 6 has comecompletely to rest on the load port 8, the hand 5 releases the wafercarrier 6 and the hand suspending part 4 is again hoisted, lifting hand5, and a transition is effected to the next carrying operation.

[0011] In such overhead-traveling carrying apparatuses, in order toavoid problems such as the dropping of objects to be carried or contactbetween objects to be carried and obstacles (not depicted in the figure)such as humans or objects which were not placed carefully, during thelowering of the objects to be carried, a variety of countermeasuresthereto have been considered from the point of view of the raising andlowering relationship between the objects to be carried by wafercarriers 6 and the load ports 8.

[0012] A conventional proposal for such countermeasures will bediscussed below with reference to FIGS. 7 through 10. Thiscountermeasure proposal was announced as a joint guidance of J300 (Japan300 mm Semiconductor Technology Conference) and I300I (International 300mm Initiative). Those structural parts which are identical to thoseexplained by FIG. 6 are given identical reference numbers, and anexplanation thereof will be omitted.

[0013]FIG. 7 shows a case in which an emergency stoppage switch 9 isprovided in the vicinity of a semiconductor manufacturing apparatus 7(in the figure, this is provided on the upper surface of load port 8),and prior to the occurrence of a problem, or after a problem hasoccurred, an operator not depicted in the figure presses this switch,and thereby stops the raising or lowering operation of the hand 5 or thewafer carrier 6. For the purposes of the explanation, these proposalswill hereinafter be referred to as countermeasure proposal A.

[0014]FIG. 8 shows a case in which a light curtain 10 is placed in frontof load port 8 using optical sensors, and when this light curtain 10 isdisrupted by an obstacle such as a person or the like, the semiconductormanufacturing apparatus 7 detects the abnormality and stops the raisingor lowering operation of the wafer carrier 6. For the purposes ofexplanation, this proposal will hereinafter be referred to ascountermeasure proposal B.

[0015]FIG. 9 shows the case in which walls 11 and manual doors 12 areprovided above load port 8, and the space above load port 8 is thuscovered. When it is necessary to gain access to the area within loadport 8 for the purposes of maintenance or the like, the manual doors 12may be opened manually; a sensor 13 which detects this open state isprovided in manual doors 12, and in the state in which manual doors 12are opened, the sensor 13 detects this and halts the raising or loweringoperation of the wafer carrier 6. For the purposes of explanation, thisproposal will be referred to as countermeasure proposal C.

[0016]FIG. 10 shows the case in which, in place of the manual doors incountermeasure proposal C, automatic doors 14 which open and closeautomatically are provided. In this proposal, as well, sensors 13 areprovided in the same manner as in countermeasure proposal C. For thepurposes of explanation, this proposal will be referred to hereinbelowas countermeasure proposal D.

[0017] However, these conventional countermeasure proposals A, B, C, andD have the following problems, and have not reached practicalapplication.

[0018] In other words, countermeasure proposal A requires theobservation of all of a large number semiconductor manufacturingapparatuses 7 by operators, and requires instantaneous decisions bythose operators, so that it is not appropriate for continuousemployment.

[0019] Furthermore, countermeasure proposals B, C, and D all require theconstructing of countermeasures at more than 1,000 spots in order to beapplied to all of the load ports 8 (generally, there are 2 to 4 of thesefor each apparatus) of a large number of semiconductor manufacturingapparatuses 7 (normally, between 300 and 400; furthermore, there areseveral tens of the carriages 3 with attached hoists in this case), sothat this causes problems in that the manufacturing costs or maintenancecosts of the semiconductor manufacturing apparatuses 7 increase.

SUMMARY OF THE INVENTION

[0020] The present invention was created in light of the abovecircumstances; the objects thereof are given below. In other words, itis an object of the present invention to provide an overhead-travelingcarrying apparatus which is capable of cheaply implementingcountermeasures which detect the contact between objects to be carriedand obstacles such as persons and objects which are not carefullyplaced, during the lowering of the objects to be carried, and avoidingthis contact.

[0021] The overhead-traveling carrying apparatus of the presentinvention adapts the following mechanisms in order to solve the problemsdescribed above.

[0022] In other words, the overhead-traveling carrying apparatus of thepresent invention is an overhead-traveling carrying apparatus providedwith a track, which is installed overhead, and carriages with attachedhoists, which travel along the track, wherein the carriages withattached hoists are provided with obstacle detecting sensors fordetecting the presence of obstacles by optically searching the raisingand lowering path between a carriage and a load port of eachmanufacturing apparatus.

[0023] In accordance with this overhead-traveling carrying apparatus, bymeans of the obstacle detecting sensor, the presence of obstaclesbetween a carriage with an attached hoist and a load port may beobserved, and when an obstacle is detected, the lowering operation of anobject to be carried may be halted prior to any interference between theobstacle and the object to be carried. A number of these obstacledetecting sensors which is smaller than that of the manufacturingapparatuses may be installed on the side of the carriages with attachedhoists, and thereby, the number of devices required can be reduced.

[0024] In the overhead-traveling carrying apparatus in accordance withother aspect of the present invention, the range of the optical searchmay be varied in accordance with the height of the load port of themanufacturing apparatus.

[0025] In accordance with this apparatus, the range of the opticalsearch may be set in advance in accordance with the height from thefloor of the load ports of the various manufacturing apparatuses, andthereby, it is possible to accommodate manufacturing apparatuses havingload ports with differing heights.

[0026] In the overhead-traveling carrying apparatus in accordance withanother aspect of the present invention, the obstacle detecting sensoris a regression reflection type which shines light onto a prespecifieddetection area on a reflector plate provided on the load port or on thefloor surface adjoining the manufacturing apparatus on the load portside which is regarded as a plane and which collects light reflectedfrom the detection area, and a control mechanism is provided which, whenthe obstacle detecting sensor collects light reflected from the totalsurface of the detection area, makes a determination that it is possibleto move the carrier of the carriage with attached hoist, and when lightreflected from the total surface of the detection area is not obtained,makes a determination that it is not possible to move the carrier.

[0027] In accordance with this apparatus, by means of the obstacledetecting sensor and the control mechanism, the presence of obstaclesbetween the carriage with attached hoist and the load port can beobserved, and when an obstacle is detected, it is possible to stop thelowering operation of the object to be carried prior to interferencebetween the object to be carried and the obstacle.

[0028] The overhead-traveling carrying apparatus according to anotheraspect of the present invention, the regression reflection type obstacledetecting sensors are installed at the carriages with attached hoists ina row in the horizontal direction.

[0029] In accordance with this apparatus, a broad planar observationrange is formed between the carriage having the attached hoist and theload port, by means of the sum of the observation areas of eachregression reflection type obstacle detecting sensor. Therein, thepresence of obstacles is observed, and when an obstacle has beendetected, the lowering operation of the object to be carried is stoppedbefore any interference between the obstacle and the object to becarried.

BRIEF DESCRIPTION OF THE DIAGRAMS

[0030]FIG. 1 is a perspective view showing a first embodiment of theoverhead-traveling carrying apparatus of the present invention.

[0031]FIG. 2 is a perspective view showing a second embodiment of theoverhead-traveling carrying apparatus of the present invention.

[0032]FIG. 3 is a perspective view showing a third embodiment of theoverhead-traveling carrying apparatus of the present invention.

[0033]FIG. 4 is a perspective view showing a fourth embodiment of theoverhead-traveling carrying apparatus of the present invention.

[0034]FIG. 5 is a perspective view showing a fifth embodiment of theoverhead-traveling carrying apparatus of the present invention.

[0035]FIG. 6 is a perspective view showing a conventionaloverhead-traveling carrying apparatus.

[0036]FIG. 7 is a perspective view showing another conventionaloverhead-traveling carrying apparatus.

[0037]FIG. 8 is a perspective view showing another conventionaloverhead-traveling carrying apparatus.

[0038]FIG. 9 is a perspective view showing another conventionaloverhead-traveling carrying apparatus.

[0039]FIG. 10 is a perspective view showing another conventionaloverhead-traveling carrying apparatus.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0040] The first embodiment of the present invention will be explainedhereinbelow with reference to FIG. 1. Structural parts which areidentical to those of FIG. 6, which depicts conventional technology, aregiven identical reference numbers, and an explanation thereof will beomitted here.

[0041] In the overhead-traveling carrying apparatus of the presentinvention, in an overhead-traveling carrying apparatus which is providedwith a track 1, which is installed overhead, and carriages 3 withattached hoists, which travel along track 1, an obstacle detectingsensor 22 is provided which optically searches the raising and loweringpath between a carriage 3 and the load port 8 of each semiconductormanufacturing apparatus 7 when the carriage 3 with attached hoist lowersa wafer carrier 6 onto the load port 8 of the semiconductormanufacturing apparatus 7, and detects the presence of an obstacle 21;this is the chief point of difference from the conventional technology,and thus the explanation will center thereon.

[0042] This obstacle detecting sensor 22 is an optical-typerange-finding sensor in which a light emitting part and a lightcollecting part which are not depicted in the figure are incorporated,and it measures the distance between the sensor 22 and the detectedobject by means of trigonometrical survey. The obstacle detecting sensor22 may be other type of a range-finding sensor, such as a sensormeasuring the distance by calculating the reflex time of light or asensor using coherent light. The obstacle detecting sensor 22 issupported by a yawing mechanism (not shown), and it scans a fan shapedscan range 20 a centering on the obstacle detecting sensor 22. Theobstacle detecting sensor 22 is connected to a computing unit (notshown), and the computing unit performs calculation for dividing thescan range 20 a using two virtual planes which are parallel in theperpendicular direction to form an observation range 20 and incorporatesdata within this observation range 20 into memory, while excluding dataoutside this range.

[0043] By means of such an arrangement, an approximately pentagonallayer of light formed between the obstacle detecting sensor 22 and loadport 8 is formed as an observation range 20. The reason for forming theobservation range 20 in this way and the reason for providing theobstacle detecting sensor 22 at the side wall 3 a are that by providingthe observation field 20 in a selective manner at the front side, whichis most likely to come into proximity with an obstacle 21 within therange of movement of wafer carrier 6, it is possible to efficientlyconduct the observation. Furthermore, the width t of the observationrange 20 is determined by the path of the light rays from the lightemitting part, so that if a laser beam is employed, it is possible tomake this width extremely narrow.

[0044] Furthermore, the observation range 20 may be varied in accordancewith the height of the load port 8 of each semiconductor manufacturingapparatus 7. That is to say, the maximum length Lmax in theperpendicular direction of the observation range 20, which is the rangein which the obstacle detecting sensor 22 conducts detection, varies bysemiconductor manufacturing apparatus 7 in accordance with the length Lain the perpendicular direction from the obstacle detecting sensor 22 tothe upper surface of each load port 8, and this may be adopted to anysemiconductor manufacturing apparatus 7.

[0045] When the wafer carrier 6 is lowered by the overhead-travelingcarrying apparatus of the present invention described above, thepresence of obstacles 21 within the observation range 20 is observed byobstacle detecting censor 22 in a non-contacting manner, and when anobstacle 21 is discovered, the lowering operation of the wafer carrier 6is halted before there is interference between the obstacle 21 and thewafer carrier 6. The number of obstacle detecting sensors 22 provided atthe side of carriages 3 with attached hoists is smaller than that of thesemiconductor manufacturing apparatuses 7, so that it is possible toreduce the numbers thereof required.

[0046] Accordingly, in accordance with the overhead-traveling carryingapparatus of the present embodiment, by providing a number of obstacledetecting sensors 22 at the side of carriages 3 with attached hoistswhich is far smaller than the number of semiconductor manufacturingapparatuses 7, it is possible to provide an overhead-traveling carryingapparatus in which inexpensively incorporates countermeasures fordetecting obstacles 21 such as people or objects placed in a carelessmanner prior to contact of wafer carrier 6 with these obstacles duringthe lowering thereof, and thus avoiding such contact.

[0047] Furthermore, by employing optical sensors as the obstacledetecting sensors 22, the confirmation of the presence of obstacles 21can be conducted in a non-contacting manner, and it becomes possible toproduce an overhead-traveling carrying apparatus which conductsobservations without damaging the obstacles 21.

[0048] Furthermore, in the setting of the observation range 20, byconducting this setting so that the maximum length Lmax in theperpendicular direction in the observation range 20 is in agreement withthe length La in the perpendicular direction between the load port 8 ofeach semiconductor manufacturing apparatus 7 and the obstacle detectingsensor 22, it is possible to provide an overhead-traveling carryingapparatus which may be adopted to all semiconductor manufacturingapparatuses 7 having load ports 8 in which the height H thereof from thefloor surface F differs.

[0049] Next, a second embodiment of the present invention will beexplain with reference to FIG. 2. Those structural parts which areidentical to those of FIG. 1, which depicted the first embodiment, aregiven identical reference numbers, and an explanation thereof will beomitted here.

[0050] In this embodiment, in place of the single obstacle detectingsensor 22 in the first embodiment, a pair of scanning-type obstacledetecting sensors 24 and 25 are provided at the side wall 3 a with afixed gap W therebetween. Sensors 24 and 25 are electro-optical sensorsfor detecting obstacles which have a net-shaped detection area by meansof scanning beams and positional detection elements (PSD), and conductdetection by means of optical trigonometric distance detection.

[0051] In this embodiment, as well, it is possible to obtain operatingeffects which are identical to those of the first embodiment.

[0052] Next, a third embodiment of the present invention will explainedwith reference to FIG. 3. Those structural parts which are identical tothose shown in FIG. 1, which depicts the first embodiment, are givenidentical reference numbers, and an explanation thereof will be omittedhere.

[0053] In this embodiment, in place of the scanning-type obstacledetecting sensors 22 which were employed in the first embodiment, anobstacle detecting sensor 26, which is capable of forming an observationrange 20 so that the light emitting and light collecting ranges have aparabolic outline which is broader toward the bottom as a result of alight source, light collecting elements, or the shape of lenses whichare not depicted in the figure, is provided on side wall 3 a. Thisobstacle detecting sensor 26 is a reflecting type which views the amountof light which is reflected, and a matted black surface treatment 27 isexecuted on the upper surface of the load port 8 so that light is notreflected from the upper surface of the load port 8 so as to causeincorrect functioning.

[0054] Operational effects similar to those of the first embodiment maybe obtained by this embodiment.

[0055] Next, a fourth embodiment of the present invention will beexplained with reference to FIG. 4. Those structural parts which areidentical to those in FIG. 1, which depicts a first embodiment, aregiven identical reference numbers, and an explanation thereof will beomitted here.

[0056] In this embodiment, in place of the single scanning-type obstacledetecting sensor 22 which was used in the first embodiment, threerange-finding-type obstacle detecting sensors 28, 29, and 30 areprovided on side wall 3 a. These obstacle detecting sensors 28, 29, and30 form the observation range 20 by the sum of the various observationareas.

[0057] This embodiment is capable of obtaining the same operationaleffects as the first embodiment.

[0058] Next, a fifth embodiment will be explained with reference to FIG.5. Those structural parts which are identical to those in FIG. 1, whichdepicts the first embodiment, are given identical reference numbers, andan explanation thereof will be omitted.

[0059] In this embodiment, in place of the scanning-type obstacledetecting sensor 22 employed in the first embodiment, a structure isemployed in which a reflector surface 41 is provided on the load port 8of each semiconductor manufacturing apparatus 7, and a regressionreflection type obstacle detecting sensor 40, which shines light onto apredetermined detection area 42 on the upper surface of reflector plate41, and which collects reflected light from the detection area 42, isattached to the side wall 3 a of carriage 3 with an attached hoist.

[0060] Furthermore, this regression reflection type obstacle detectingsensor 40 is connected to a control mechanism which is not depicted inthe Figure. When reflected light is received from the entire surface ofthe detection area 42 by the obstacle detecting sensor 40, the controlmechanism sets the output to ON, and determines that “the presence ofthe entire surface of reflector plate 41 has been confirmed, so thatcarrier 6 can move.” On the other hand, when reflected light has notbeen obtained from the entire surface of detection area 42 in obstacledetecting sensor 40 (that is to say, as viewed from the side of obstacledetecting sensor 40, an obstacle 21 is obstructing the detection area 42at some point, or reflector point 41 is not positioned directly below),the output is set to OFF, and the control mechanism makes thedetermination that the movement of carrier 6 is impossible.

[0061] When the range which is to be detected by the structure of eachsemiconductor manufacturing apparatus 7 becomes limited, by employingthe detection area selection function provided in the obstacle detectingsensor 40, it is possible to restrict the width of the detection area.On the other hand, when it is necessary to broaden the detection area asa result of a large-sized overhead-traveling carrying apparatus or thelike, by employing the mutual interference protection function (aswitching function of the projected light frequency) provided inobstacle detecting sensor 40, it is possible to cover a broad detectionarea using a plurality of obstacle detecting sensors 40.

[0062] Furthermore, in the present embodiment, a structure is adopted inwhich the reflector plate 41 is provided on the load port 8; however,when it is difficult to install this plate on the load port 8, it isalso possible to provide the plate on the floor surface F which adjoinsthe apparatus 7 in front of load port 8 and which is regarded as a plane(the area 45 depicted by the double dotted line in FIG. 5).

[0063] Operational effects identical to those of the first embodimentmay be obtained using this embodiment as well.

[0064] In the first through fifth embodiments of the present inventiondescribed above, obstacle detecting sensors 22, 24, 25, 26, 28, 29, 30,and 40 were provided on the side wall 3 a of the carriage 3 withattached hoists; however, this is not necessarily so limited, insofar asobstacles 21 within an observation range 20 containing one or both ofthe movement range during the lowering of the wafer carrier and thevicinity of the movement range may be detected; these sensors may beaffixed at other spots, such as the front or back or lower end of thecarriage 3 with attached hoist, or a structure may be employed in whicha plurality of sensors are installed at different points.

[0065] Furthermore, the obstacle detecting sensors 22, 24, 25, 26, 28,29, 30, and 40 which are shown in the first through fifth embodiments ofthe present invention only represent examples; these are not necessarilyso limited, and other types of optical sensors may be employed.

[0066] Furthermore, in the fourth embodiment of the present inventiondescribed above, a structure was adopted in which threerange-finding-type obstacle detecting sensors 28, 29, and 30 wereprovided on side wall 3 a; however, in place of this, it is alsopossible to adopt a structure in which sensors similar to the regressionreflection type obstacle detecting sensors 40 in the fifth embodimentare provided at a plurality of spots (for example, 3) on side wall 3 a,and a similar reflector plate 41 is provided on load port 8 (notdepicted in the figure), and in which an observation range 20 is formedby the sum of the observation areas of these obstacle detecting sensors.In this case, as well, it is possible to obtain operating effects whichare identical to those of the first embodiment. When it is difficult toinstall the reflector plate 41 on load port 8, as well, it is possibleto provide this on the floor surface F which adjoins the apparatus 7 infront of load port 8 and which is regarded as a plane.

[0067] Furthermore, in the fourth embodiment of the present inventiondescribed above, three obstacle detecting sensors 28, 29, and 30 wereemployed; however, this is not necessarily so limited, and a numbersufficient to form an observation range having sufficient breadth orsize may be employed, so that two or four or more may be employed.

[0068] Furthermore, in the first through fifth embodiments describedabove, an example was explained in which the overhead-traveling carryingapparatus of the present invention was installed in a semiconductormanufacturing facility which conducted the manufacturing ofsemiconductor devices by processing semiconductor wafers; however, thisis not necessarily so limited, and the present invention may be adaptedfor factory automation lines in factories, or other facilities.

[0069] In accordance with the overhead-traveling carrying apparatus ofclaim 1 of the present invention, by providing a number of obstacledetecting sensors at the side of the carriages with attached hoistswhich is much smaller than the number of manufacturing apparatuses, itis possible to provide an overhead-traveling carrying apparatus which iscapable of inexpensively incorporating countermeasures which detectobstacles such as people or carelessly placed objects prior to thoseobstacles coming into contact with objects to be carried during thelowering thereof, thereby avoiding such contact.

[0070] Furthermore, in accordance with the overhead-traveling carryingapparatus in accordance with claim 2 described above of the presentinvention, in the setting of the observation range, the optical searchrange is set in advance in accordance with the height of the variousload ports of each manufacturing apparatus, and thereby, it becomespossible to provide an overhead-traveling carrying apparatus which iscapable of accommodating all manufacturing apparatuses having load portsof differing heights.

[0071] Furthermore, in accordance with the overhead-traveling carryingapparatus of claims 3 and 4 of the present invention, effects identicalto those obtained in claim 1 may be obtained.

What is claimed is:
 1. An overhead-traveling carrying apparatus providedwith a track, which is installed overhead, and carriages with attachedhoists, which travel along the track, wherein said carriages withattached hoists are provided with an obstacle detecting sensor fordetecting the presence of obstacles by optically searching a raising andlowering path between a carriage and a load port of each manufacturingapparatus.
 2. An overhead-traveling carrying apparatus in accordancewith claim 1, wherein a range of said optical searching may be varied inaccordance with the height of said load port of said manufacturingapparatus.
 3. An overhead-traveling carrying apparatus in accordancewith claim 1, wherein said obstacle detecting sensor is a regressionreflection type which shines light onto a prespecified detection area onat least one of a reflector plate provided on said load port and a floorsurface adjoining said manufacturing apparatus on said load port sidewhich is regarded as a plane, and which collects light reflected fromsaid detection area, and wherein a control mechanism is provided which,when said obstacle detecting sensor collects light reflected from thetotal surface of said detection area, makes a determination that it ispossible to move a carrier of said carriage with attached hoist, andwhen light reflected from the total surface of said detection area isnot obtained, makes a determination that it is not possible to move saidcarrier.
 4. An overhead-traveling carrying apparatus in accordance withclaim 3, wherein said regression reflection type obstacle detectingsensors are installed at said carriage with attached hoists in a row inthe horizontal direction.
 5. An overhead-traveling carrying apparatus inaccordance with claim 1, wherein said obstacle detecting sensor is arange-finding sensor comprising a light emitting part and a lightcollecting part, and said obstacle detecting sensor scans a fan shapedscan range centering on said obstacle detecting sensor; and wherein theoverhead-traveling carrying apparatus further comprises a computing unitfor processing signals output from said range-finding sensor andexcluding data outside a range below said carriages.
 6. Anoverhead-traveling carrying apparatus in accordance with claim 1,wherein said obstacle detecting sensor comprises a pair of scanning-typeobstacle detecting sensors provided with a fixed gap therebetween, andeach of said scanning-type obstacle detecting sensors has a net-shapeddetection area by means of scanning beams and conducts detection bymeans of optical trigonometric distance detection.
 7. Anoverhead-traveling carrying apparatus in accordance with claim 1,wherein said obstacle detecting sensor is capable of forming a lightemitting and light collecting range having a parabolic outline which isbroader toward the bottom, and the upper surface of said load port is amatted black surface.
 8. An overhead-traveling carrying apparatus inaccordance with claim 1, wherein said obstacle detecting sensorcomprises a plurality of range-finding-type obstacle detecting sensors.9. An overhead-traveling carrying apparatus in accordance with claim 1,further comprising at least a reflector provided on said load port ofeach semiconductor manufacturing apparatus, and wherein said obstacledetecting sensor is a regression reflection type obstacle detectingsensor for shining light onto said reflector and collecting reflectedlight from said reflector.